Instantaneous detonator for hollow charge projectiles



L. T. MEISTER Dec. 27, 1955 INSTANTANEOUS DETONATOR FOR HOLLOW CHARGEPROJECTILES 4 Sheets-Sheet l 1 Leu T- Meia cer Filed Feb. 27, 1945 L. T.MEISTER INSTANTANEOUS DETONATOR FOR HOLLOW CHARGE PROJECTILES 4Sheets-Sheet 2 Filed Feb. 2'7, 1945 arwcm/m LED T. Meilaier Dec. 27,1955 L. T. MEISTER 4 Sheets-Sheet 3 Filed Feb. 27, 1945 NMQ mw, W /7 M mmsfi mmm mfiwwmmmwmmmmmmmmmmmmmhpl F y I LED T- Mei-slap 3 axmbwm D c-27, 95 1.. T. MEISTER 2,728,296

INSTANTANEOUS DETONATOR FOR HOLLOW CHARGE PROJECTILES Filed Feb. 27,1945 4 Sheets-Sheet 4 LEE] T. MEiErcEr United States PatentINSTANTANEOUS DETONATOR FOR HOLLOW CHARGE PROJECTILES Leo T. Meister,Bradley Beach, N. J. Application February 27, 1945, Serial No. 580,066

16 Claims. or. 102-701 (Granted under Title 35 U. S. Code (1952), see.266) jectile casing can be crushed by impact with the target. I

The use of a shaped charge having a conical cavity resulting in aconcentration of the blast leaving the cavity into a jet of intensepenetrating power has been known for a long time. The development ofsuch a cavity charge for military purposes has only come into generaluse in the present war and as a result of the discovery of a greatlyimproved result through the introduction of a thin wall steel cone as aliner for the cavity. These lined cavity charges form jets much moreintense and persistent than an unlined cavity. As the present inventiondoes not relate to the charge cavity, per se, a discussion of the causeof the resulting jet will not be undertaken except to state thatexperiments have proved that it follows a course in axial alignment withthe axis of the conical cavity. Likewise, the present invention is notconcerned with the angle of the apex of the conical cavity which can bevaried, since the critical angle for any particular charge can bereadily ascertained by trial and error.

The present invention is principally concerned with providing means forovercoming a serious defect which results when such cavity charges areused in projectiles. This defect arises from two causes. First, withdetonators now in use the detonation is not sufficiently quick to occurbefore the shell case is crushed by impact with the target, andconsequently, the cavity of the charge is deformed before the chargeoccurs thus destroying or practically destroying the resultingpenetrating jet. Second,

in order for the penetrating jet to function with maximum efliciency acritical standoff distance is essential. This is lost where the nose ofthe projectile is crushed before the detonation occurs, so that toovercome this and the first mentioned shortcoming of shaped cavitycharges, an improved detonator is required which will detonate thecharge before the projectile case canbe crushed or deformed and beforethe nose of the projectile can penetrate the target. i

It is therefore the primary aim of this invention to provide a detonatorfor shaped charges which is s ubstantially instantaneous and which willdetonate the charge before the projectile case can be crushed to deformthe charge cavity and before the nose of the projectile can penetratethe target sufficiently to elfect the critical standoff distance of theresulting jet.

As previously mentioned the .penetrating jet follows a pathcorresponding to the axis of the cavity and in order that its maximumefiect can be obtained the path. of the jet must be unobstructed.

It is therefore a further aim of the present invention to provide adetonator which so constructed that it will path of, the" tary sectionalview of one form of the invention incorporated in a projectile;

Figure 2 is a similar view showing the parts in the positions assumed atthe instant of detonation;

Figure 3 is a cross sectional view of the detonator taken substantiallyalong a plane as indicated by the line 3-3 of Fig. 1;

Figure 4 is an enlarged fragmentary perspective view of one-half of afield coil and the permanent magnet, shown withdrawn therefrom;

Figure 5 is a fragmentary longitudinal sectional view, on an enlargedscale, of a slightly modified form of the embodiment shown in Figs. 1 to4;

Figure 6 is a longitudinal substantially central sectional view of aprojectile and showing another embodiment of the invention; i

Figure 7 is a longitudinal, fragmentary substantial central sectionalview of the same and showing the detonator parts in the positions theywill assume at the instant of detonation;

Figure 8 is a longitudinal substantially central sectional view ofanother embodiment of the invention shown in conjunction with an aerialbomb;

Figure 9 is an enlarged central sectional view of a tion of the deviceshown in Fig. 8;

Figure 10 is a similar view of another portion device of Fig. 8;

Figure 11 is an enlarged longitudinal, substantially central sectionview of a fuse, illustrating another embodiment, of the invention, and In Figure 12 is a View similar to Fig. 11 and showing a modification ofthe fuse disclosed therein. a

Referring more particularly to the drawings,'wherein of the i likereference characters designate like or corresponding parts throughoutthe different views, and referring particularly to Figs. 1 to 4, 15designates generally an artillery projectile including a casing 16composed of a nose section 17, a trailing section 18 and a plug 19 whichthreadedly engages and closes the open rear end of the trailing orcharge section 18. Section 18 is internally threaded at its forward endto engage the externally threaded rear end of the nose section 17, asseen at 20. The nose sec tion 17 is provided with a movable impactreceiving nose portion 21 which is connected to the section 17, forsliding movement relative thereto, by means of a sleeve 22 whichslidably engages an opening 23, in the forward end of the nose section17; and which is provided with a flared inner end which normally bearsagainst the interior of the section 17, to retain the sleeve 22 and thenose portion 21 in position. The trailing section or charge chamber 18contains a shaped charge of high explosive 24 which is provided with aconical cavity 25 in its forward endfa circular cavity 26 in its rearend and an axially disposed bore 27 connecting the cavities 25 and 26.Cavity 25 is lined with a thin steel wall 28 (shown greatly exagger-fated as to thickness in the drawings) which is integral with the tube 29which lines the bore 27 and which exthreadedly engaging the rear end ofthe tube 29.' An:

annular field coil 32, comprising a winding 33 and an inwardly openingannular metal channel member 34, is molded in the block 3i] around andin communication with the bore 31. As thus seen in Fig. 4, the channelmember :34is divided circumferentially into corresponding sections 35. Arod 36 slidably engages the tube 29 and has one end projecting therefrominto the bore 31, and to, which is threadedly connected a permanentmagnet 37 which is disposed in thefield coil 32 and mounted for moyeme twith the rod 36 relatively thereto. Rod 36 is provided with alongitudinally disposed slot 38 into extends a guidescrew 39, which ismounted in the tube 29, to prevent rotation of rod 36 and the magnet 37.A small booster chamber 40 is mounted in the rear end of the bore 31andcontains a conventional electrical detonator or squib 41 of the typeprovided with a very light resistance wire, so that a very slightelectrical charge is -sufl icient todetonate the squib 41. Between therear end of the tube 29 and the magnet 37, one or more spring washers 42are mounted on the rod 36 to yieldably urgethe magnet 37 rearwardly andagainst chamber 45 to normally hold the magnet in fixed positionrelatively to the field coil 32. I The insulating block 30 is providedwith an annular, tubular chamber 43 containing a small quantity ofmercury 44. The block 30 is divided transversely through'the chamber 43andconnected by fastenings 45 to afford a simple means of forming thechamber 43, but obviously said chamber could 'be formed in l w? su ta mAnelectrical conductor 46 has one end secured in the chamber 43 and itsopposite end connected to the field coil 32. An electrical conductor 47,forming one lead of the electrical detonator has an end extending intothe chamber 43, and in spacedapart relationship to the conductor 46. Theends of the conductors 46 and 47 which extend into the chamber 43 areretained therein by set screws 48. A conductor 49, forming the otherlead of the detonator 41 extends therefrom to the field coil 32. A cap50 threadedly engages the rear end of the block fgtl and fills therearportion of the recess 26 and c'ombines with blocl; 30 to form a chambercontaining a high explosive forming a booster charge 51. Theheadofthecap 50 is seated in a recess in the inner end of the plug 1?.plurality of small bellcranks 52 are -fulcrumed at their apexe's in theforward end of the nose'section 17 by arch shaped pins 53 which extendinto the section 17. The lev'ers 52 have corresponding ends bearingagainst the inner flared end of the sleeve 22 and the opposite endsofthe levers 52 are connected-to corresponding ends of wires or flexiblemembers 54. The opposite ends of the wires 54 are securedto the forwardend of-the rod 36. Wires 54 slidably engage U-shaped guide members 55,the ends of which are secured in the nose section 17 for retaining thewires 54 away from the longitudinal center of the projectile-15, for-apurpose that willhereinafter become apparent.

H In the form of the invention shown in Figs. 1 to 4, the projectile 1is of the character adapted to be fired from a rifled barrel and whichis rotated thereby in flight. It will be apparent that the projectile 15prior to being fired is rendered-safe dueto the'fact that the circuitfrom ;the field coil 32 to the detonator 41 isinter ruptedby the gapbetween the conductor 46 and the conductor '47. Consequently, shouldthe'magnet 37 be in advertentlymoved relative to the coil 32 theelectrical current-produced wouldnot be conducted to the detonator 41.Thus,.the fuse, constituting the parts contained in the block 30, is inan unarmedconditionprior to the time the projectile 15 is fired.Upon-being fired,-it will be apparent that the projectile 15 will berotated on" its longitudinal axis during flight thus causing the mercury44, due to inertia, to be spread out into a fine "stream or'ribb'onaround the outer part of the chamber 43,as seen in Fig.- 2, to thuscomplete a connection between conductors 46 and'47 through thesti'eamofmercury-44,

' 4 In this manner the fuse is armed. Upon striking a target the noseportion 21, on contact with the target, will be forced rearwardlyrelatively to nose section 17, from its position of Fig. 1, to itsposition of Fig. 2. This rearward movement of portion 21 willbetransmitted to sleeve 22 which in turn will engage and rock the bellcranks 52 to exert a pull on the wires 54 which will be transmittedthereby to the rod 36 and the permanent magnet 37, to move the permanentmagnet forwardly, relatively to coil 32. A very slight movement of themagnet 37, much less than that shown between Figs. 1 and 2, is adequateto produce sufiicie'nt electrical current in the coil 32 to detonate thesquib 41, which will in turn successively detonate the booster 51 andthe charge 24. Charge 24 upon being detonated will produce an intensepenetrating jet, not shown, which will pass axially through nose section17, sleeve 22 and the thin forward end of the nose portion 21 and intothe target, not shown. The flexible actuating members 54 are extendedalong the casing section '17 instead of through the center of theprojectile 15, so as not to interfere with the jet produced by thecharge 24. Furthermore, it will be apparent that the charge 24 isdetonated at the instant the nose portion 21 is moved rearwardly byimpact, so that the detonation is produced before any part of theprojectile casing can be crushed, 'inor'der that the cavity 25 will notbe deformed; and so that the critical standoii distance between saidcavity and the forward end of the projectile will exist at the time ofthe detonation of the charge 24. In Fig.5 a slightly modified form ofthe embodiment, shown in Figs. 1 to 4 is disclosed. In this embodiment,in lieu of the block 30, a block 56 0f non-magnetic material, such-asbrass, is provided. Block 56 is provided with a recess '57 communicatingwith a restricted forwardly extending, .for-wardly opening bore 58. Afront plate 59 issecured byffastenings v6i) to the forward :face of theblock 56 and is provided with an opening 61, larger'than the bore 58,'for receiving a metal liner 62, which replaces the 'liner 29, and whichis provided with a flared rear end 63 which is clamped between portionsof'block'5 6and plate '59. A rod-64, the rear end at least of'which isformed of'an electrical insulating material, is slidably mounted in.thetubularliner 62 and bore 58 and is provided with an enlarged head65, of the same material, which .is reciprocallymounted in the recess57. Between the'head 65 and 'the inner endof the recess 57 aremounted'a. plurality of spring washers 66 which urge the head 65rea'rwardly an'd to the position of Fig. 5. The r0864 is Yprovidedwithan opening 67 which extendsdia'metrically'therethrough, and which isrelatively wide in a directionflengthwise thereof. A pin 68-is disposedin the block 56 and extends'loosely through opening "67 tolimit thereciprocating 'movement of the rod 64 and itsneaa'asam to preventrotation of either the rod "or head. r

'Hea'd "65'is provided with an annular chamber 69, formed in the samemanner and'ffor the'samepurpose as the chamber '43,: andcontaining asmall quantity of mercury 70. A fie1'd'coil'71is mounted in-a recess ofthe head 65 and includes :a winding '72 and an outwardly openingchannelmember '73 of metal in which the-winding is contained. ,Apermanent annular or-ringshaped magnet 74' issea'te'd in'the' block56land'defines the outer end for "the recess 57 and encompasses the fieldcoil "71. Head"6 5"isprovidedwith an""outwardly opening recess forcontaining "an electrical "detonator 75, "corresponding to-the'detonator 4mm having an electrical conductor76 leading" therefrom to thecoil" 71, and 'a second electrical conductor 77 leading therefrom to acontact '78, which extends "into the annular chainb'er"69. "Anelectrical 'conductor' 79' -leadsTfrom the fieldicoil 71ftoan-electricalcontact 80,"which likewise' extends: into the'annularchamber 69, andwhich is remotely disposed relatively to the contact 78. A cap :81- isthreadedlyi connected to the block 56* and =has' a closedend =s'pao'edtherefrom. A wall or f partition 82 forms a chamberin the outer end ofthe cap 81 which contains a charge of high explosive forming a boostercharge 83 positioned to be exploded by the detonator 75.

In the embodiment disclosed in Fig. 5, the functioning of the noseportion 21 and the wires 54 will be the same as heretofore described, aswell as the detonation ofthe explosive charge, and the jet producedthereby. The fuse structure of Fig. 5 will function in a slightlydilferent manner due to the fact that the field coil 71 is operativelyconnected to the rod 64, so that'coil 71 will be moved forwardly,relatively to the permanent magnet 74, by the pull exerted on the rod 64through the wires 54, not shown in Fig. 5. This movement of the coil 71,relatively to the magnet 74, will produce the electric current fordetonating the squib 75 by the circuit previously described. It will beunderstood that the fuse assembly shown in Fig. 5 is likewise intendedto be mounted in a rotating type projectile so that at thetime the rod64 is actuated the mercury will be making an electrical connectionbetween the spaced contacts 78 and 80, to complete the circuit betweenthe coil 71 and the detonator 75. Squib 75 will detonate the booster 83which in turn will detonate the explosive charge, not shown. The pin 68will prevent rotation of the rod 64 and the head 65 to thereby preventany rotation of the coil. 71, contained in the head 65, relatively tothe magnet 74, which might otherwise cause premature detonation of theprojectile while in flight.

Figures 6 and 7 show another embodiment of the invention incorporated ina projectile of the rocket type and which is characterized by being of anon-rotating construction. In Fig. 6, 84 designates generally theforward end of such a projectile and which includes a nose section 85and a trailing section 86. The nose section 85 is provided with amovable nose portion 87 which is hollow and to which is threadedlyconnected an annular member 88, preferably formed of brass. The forwardend of the projectile casing 84, formed by, the nose section 85, is openand internally threaded to receive and threadedly engage a plastic ringmember 89, in which is seated a field coil 90, composed of a winding 91which is mounted in a metallic member 92, which is angular in crosssection. The member 92 has one side thereof forming the peripheryof thecoil and an inwardly disposed fiange, forming the forward end of thecoil 90, so that the inner side and the rear face of the winding 91 isexposed. A ring magnet 93 is reciprocally mounted in the field coil 90and includes an annular portion which is disposed within the coil 90 andan outwardly projecting flange which normally bears against the innerexposed side of said winding. The annular member 88, at its inner end,is offset inwardly to overlap a portion of the permanent magnet 93, andis secured thereto by fastenings 94. The enlarged rear end of the nosesection 85 is internally recessed to provide a seat for the open,forward end of the trailing section 86 and the joint thus formed issecured in any suitable manner as .by welding at 95'. Section 86 forms achamber for a charge of high explosive, designated 95, which is providedwith a conical cavity 96 at its forward end provided with a lining 97 ofsteel, which is relatively thin. The conical lining 97 has a flangedmonth which is clamped in the joint formed by the sections 85 and 86.;The opposite end of the charge 95 is recessed to partially receive abooster charge 98. Section 86 is provided with a restricted rear portionwhich is, internally threaded to receive and engage a fuse housing 99which in turn contains a forwardly opening recess 100 for threadedlyengaging the rear end of the booster chamber 98, and into which opensthe forward end of a bore 101 that extends longitudinally through thehousing 99. Bore 101 contains a recessed insert 102, in the forward endthereof, having an opening 103 which communicates with the boostercharge 98 and whichis recessed to seat the forward endof an electricdetonator or squib 104 and to threadedly engage the forward "restrictedend of an insert- 105, which is formed'of an electrical insulatingmaterial. One of the conductors 106 of the detonator 104 is grounded tothe casing of the projectile 84 and the other conductor 107 thereofextends forwardly through a bore 108, in the restricted rear part of thesection 86, through the charge 95 and the wall 97, and through theinterior of the nose section 85, and is connected at its opposite end tothe field coil 90. Another conductor 108 leads from the field coil 90and is grounded to the projectile casing. The conductor 107 is providedwith a casing of insulating material 109 to electrically insulate itfrom the projectile casing. A shorting wire 110 has its ends embedded intheinsert and extends across and is in electrical contact with theconductors 106 and 107, and therebetween, extends across a chamber 111in insert 105. Chamber 111 contains a setback operated weight 112 whichis loosely mounted therein and through which the intermediate portion ofthe shorting wire extends.

In order to assemble the projectile 84, the plastic ring 89 is firstapplied after which the annular member 88 is connected to the magnet 93.The conductor 107 is then connected to the coil 90 and the conductor 108of the coil is connected to the projectile casing, after which the noseportion 87 is applied. The lining 97 is seated in the nose section 85,after conductor 107 has first been passed therethrough and through thebore 108, after which the section 86 is seated in the section 85 and theannular weld 95' is then formed. The charge 95 is then inserted throughthe rear end of the section 86 and tamped in place and the boosterrecess formed therein; after which the booster and the fuse housing 99are applied, with their inserts 102 and 105. The conductor 106 can thenbe connected to the projectile casing and a connection made between theends of the conductor 107, adjacent the detonator 104.

From the foregoing, it will be obvious that parts of the projectile 84will be in the positions, as seen in Fig. 6, prior to the time theprojectile is propelled from a launcher tube or rails, not shown.Consequently, although the nose section 87 is frictionally held againstmovement relative tothe nose section 85, by frictional contact with theplastic member 89 of the forward part 85, should relai tive movementoccur which would produce an electric current in the coil 90, the wirewould short this current to prevent the detonator 104 from beingenergized so that the shorting wire 110 functions as a safety means tomaintain the fuse in a disarmed condition, prior to discharge of theprojectile. Upon discharge of the projectile, the weight 112 will be setback, shearing the shorting wire 110, between the conductors 106 and107, as seen in Fig. 7, to thereby destroy the function of the shortingwire 110, and to arm the fuse. Upon impact of the nose portion 87 with atarget, said nose portion 87 will be forced rearwardly relative the nosesection 85, as seen in Fig. 7, for transmitting this rearward motion tothe permanent magnet 93 through the annular member 88. This will causemagnet 93 to move rearwardly relative to the coil 90, and a very slightmovement of the magnet 93 is adequate to produce a sufficient electriccurrent in the coil 90 to energize and detonate the squib 104, which isof the same type as squib 41. The type of coil and magnet shown in Figs.6 and 7 is especially eflfective'due to the fact that an air gap iscreated along each edge of the magnet, which materially increases theelectric current produced. The detonation of the squib 104 detonates thebooster 98 which in turn detonates the charge 95. As in the form of theinvention previously described, the cavity 96 results in an intensepenetrating jet being produced by the charge 95, which is projectedaxially through the forward part of the projectile 84 and through thenose portion 37. In order that the conductor 107 will not be in the pathof this jet, not shown, said conductor-ex tends along the projectilecasing wall, as seen in Fig. 6.

As in the previous embodiment of the invention, it will be readilyapparent that this detonation of the charges 95 will be produced atsubstantially the instant of impact of the nose portion 87 with thetarget, and before any part of the projectile casing can be crushed andbefore and substantial penetration of the target occurs, so that thecavity 96 Will not be deformed, and the critical standoff distance forthe charge will still exist at the time that the jet is produced.

In Figs. 8, 9 and another embodiment of the invention is disclosed andin conjunction with an aerial bomb, for which said embodiment isespecially adapted. The bomb, designated generally 113, is provided with:1 casing including a nose section 114 and a trailing section 115. Amovable nose portion 116 is reciprocably mounted relatively to thesection 114 and is connected thereto by means of an annular member 117,which threadedly en gages the nose portion 116 and which frictionallyengages the open forward end 118 of the nose section 114. Member 117 isformed of a non-magnetic material such as brass. A permanent ring magnet119 is frictionally retained in the opening 113 and is disposed directlybehind the member 117. A field coil 120, comprising an annular winding121 and an annular inwardly opening channel member 122, in which thewinding 1.21 is seated, is seated in a non-magnetic Wall in the interiorof the nose section 114 and adjacent its open forward end 118. The openrear end of the nose section 114 is internally recessed to receive theopen forward end of the trailing section 115 which is seated therein,and said sections are secured together by an annular weld 123. Thesection 115 forms a. charge chamber for a charge of high explosive 124which is provided with a forwardly opening conical recess 125 having athin Walled steel lining 126, the flanged open end of which is clampedbetween the sections 114 and 115. The rear end of the charge 124 isrecessed to receive a booster 127 and a fuse housing 128. The casing 115is provided with a restricted open rear end which is annular andinternally threaded, as seen at 129, to receive a recessed plug 130,which is threadedly engaged therewith, and which is provided with acentral opening 131 through which a portion of the housing 128 extendsand which is threadedly secured thereto.

Referring particularly to Fig. 10, housing 128 is formed of a forwardsection 132, an intermediate section 133 and a rear section 134. Section132 is provided with a restricted intermediate portion which extendsinto and threadedly engages the internally threaded open forward end ofthe section 133. Section 133 is hollow throughout its length and isprovided with a forwardly facing step or shoulder 13S, intermediate ofits ends. The inner end of the forward section 132 is provided with anannular restricted portion 136, forming a rearwardly facing shoulder 137and a restricted rear end 138. Section 132 is provided'with .a bore 139which extends longitudinally therethrough, and the inner end of which isrestricted to form a seat for a percussion cap 140. A hollow sleevememher 141 is slidably mounted in the section 133 and has reciprocablymounted therein a cup-shaped firing pin 142. The nipple of the firingpin 142 faces toward and is aligned with percussion cap 140 and uponforward movement is disposed to engage and detonate the percuss-ion cap.The hollow interior of the firing pin 142 houses and seats an expansionspring 143 which bears against the forwardly facing shoulder, adjacentthe rear end of the sleeve 141, for normally urging the firing pinforwardly. Sleeve 141 is provided with radial openings 144 containingsolid balls 14-5, which bear against the interior of the section 133,rearwardly of the shoulder 135., and which are held thereby so as topartially extend into the interior of the sleeve 141, to engage theforward end of the firing pin 142 to form detent-s for holding thefining .pin in a retracted position and against theaction of the :spring143.. An expansion coil spring 146 has one end :se'ating against theshoulder 137 and 8 the cohvoIut-ibn's'the'rc'of, attire opposite end ofsaid spring, are reduced in diameter to bear against the forwardlyfacing shoulder 147, of the sleeve 141, for urging the sleeve rearwardlyof the housing 128.

A shaft 148 is provided with a forward end having a left hand threadwhich extends through and threadedly engages a threaded opening 149, inthe section 154, and a threaded opening 150, in the rear end of thesleeve 141. The shaft 148 is journaled adjacent its rear end in abearing 151 and behind said bearing an arming vane 152 is keyed to theshaft. The blades of the arming vane 152 are pitched so that during thedescent of the bomb 113 the arming vane 152 will be rotated by thepressure of the air impinging thereon to turn the shaft 148, so as tounscrew the shaft from the threaded portion 150. The arming vane 152 isrotated sufficiently to unscrew the shaft 148 from the threaded openingof the sleeve 1-l1 during approximately the first 600 feet descent ofthe bomb 113, for arming the mechanical fuse mechanism, previouslydescribed, so that upon impact of the bomb with a'target, the sleeve 141will be driven forward by inertia and against the action of the spring146. When the sleeve 141 moves forward sutliciently so that the spheres145 pass the step formed by the shoulder 135, said spheres will beprojected radially outward by the pressure of the spring 3143, hearingon the firing pin 142, to permit it to be projected forwardly in thesleeve 141 and into engagement with the primer 140, for detonating theprimer. The bearing 151 is supported by a sleeve 153, as best seen inFig. 10, through which the shaft 148 extends. Bearing member 151contains reduction gears, not shown, and which form no part of thepresent invention.

The forward fuse housing section 132 contains an electric detonatingmeans which is mounted in the enlarged forward end of its recess 139 andwhich is contained in a block 154, of an insulating material, which isheld in the forward part of the recess 139 by a threaded block 155having a centrally disposed opening 156 which communicates at itsforward end with a booster 127 and at its rear end with a secondarybooster 157, in which is disposed an electric detonator or squib 1S8,corresponding to the squib 41, previously described. Behind the block154, the recess 139 is provided with an insert 159'v having'a passage1'60 extending therethrough, to combine with the rear portion of therecess 13S and the opening 156 to form a flash passage from the primer140 to the booster charge 127.

Two electrical conductors 161 and 162 extend from field coil 12-0 alongthe interior of the wall of the bomb casing and through the conicallining 126 and the charge 124 and are connected to and form a part ofthe two electrical conductors of the detonator 158. Between the cell 120and thefuse housing 12% the conductors 161 and 162 are encased in a tubeof electrical insulating material 163.

A safety device, designated generally 164, is mounted intermediate ofits ends in the nose section 114, by means of the fastenings 165, andextends through the casing thereof. Said safety device 164 includes acylinder 156 which extends through the casing section 1.14 and which, atits inner end, is provided with a threaded plug 167 which is threadedtherein and adjustable relatively thereto. Plug 167 provides a bushingfor a reciprocating rod 168, which extends therethrough and which isconnected at its inner end to a hydraulic piston 169. An expansionspring 170 abuts against the plug 167 and against the piston 16? forurging the piston inwardly of the cylinder 166, and said plug i6! isprovided with openings, as seen in Pig. 9, for venting the cylinder 166"behind the piston 169. Cylinder 165, adjacent its opposite end, isprovided with a restricted outlet port 171, normally sealed by a closure1'72 containing sealing gaskets 173. Closure 172 is slidably mounted andis provided with an eye 1'74 inits head which registers with alignedopenings 175 in the outer part of the cylinder 166, when the closure 172is in a fully seated position, to receive a safety pin 176. Pin 176positively retains the closure 172 in sealing engagement with the port171. Beyond the opening 174 the closure 172 is provided with a secondeye 177 which aligns with corresponding openings 178 in the outer partof the cylinder 166 for receiving an end of an arming wire 179. Thearming wire 179 extends through and slidably engages guide members 180which are mounted exteriorly of the bomb casing. The opposite end of thearming wire 179 extends through and slidably engages an opening ornotch, not shown, in the flange 181 of the bearing 151 and through oneof the blades of the arming vane 152, or between the blades thereof, toprevent rotation of the arming vane 152 while the arming wire 179 isapplied, as seen in Fig. 8. Between the guide members 180, the armingwire 179 is provided with an eye 182 which is adapted to be connected toflexible anchor means, not shown, attached to an aircraft, not shown,from which the bomb113 is to be launched for a purpose hereinafter to beexplained. Referring back to the cylinder 166, said cylinder contains ahydraulic fluid as indicated at 183'which is held under pressure by thespring pressed piston 169, and it will be readily apparent that thepressure of the fluid can be varied by advancing or retracting the plug167, relatively to the cylinder 166. A bracket 184, of insulatingmaterial is fastened to the exterior of the cylinder 166, adjacent itsinner end, and provides a guide .for one end of an angular electricalcontact 185, the other end of which is secured to the outer end of thepiston rod 168. A fixed electrical contact 186 is fastened to thebracket 184, above and normally spaced from'the upstanding end of thecontact 185. The conductor 161 is divided intermediate its ends and hasone end thereof connected to the fixed contact 186 and its other endconnected to the movable contact 185, as best seen, in Fig. 8.

The bomb 113 is assembled in the same manner as the projectile 84, aspreviously described.

.As previously mentioned the bomb 113 is intended to be launched from anaircraft in any conventional manner, not shown, but prior thereto thesafety pin 176 is removed. A flexible connector, previously mentionedand not shown, attaches the arming wire 179 to the aircraft so that whenthe bomb 113 is launched the arming wire 179,.will. be strippedtherefrom. This will cause one end of the arming wire to be moved out ofengagement with the openings 178 and the opening 177 of the closure 172,to release said closure, which is being held by the arming wire 179,after removal of the safety pin 176. The pressure of .the fluid 183will'force the closure 172 away .from the port-171 to expose this portto allow the fluid 183 to be ejected therethrough thus permitting thepiston 1 69to move inwardly of the cylinder 166 under the actionof thespring 170. As the piston 169 moves inwardly, the piston rod 168 willmove therewith carrying.

the movable contact 185 which will be moved thereby into engagement withthe contact 186 for completing the circuitbetween the field coil 120andthe detonator 1515. Likewise, the arming wire 179 when stripped fromthe bomb 113 will release the arming vane 152-which will be actuated, aspreviously described, to arm the mechanical fuse shown in Fig. 10, inthe manner heretofore described.

The arming vane 152 requires approximately six seconds.

to arm the mechanical fuse and by adjustment of the plug. 167,,thelength of time required, for the piston 169- to .move sufficiently topermit contacts 185 and 186 to close the circuit between the coil 120and the detonator 158, can be adjusted to arm the electric fuse atapproxi mately the same time.

Uponirnpact of the nose portion 116 with a target, said nose portionwillmove inwardly relative to the nose section 114 thereby forcing theannular member 117 inwardly, which in turn will move the permanentmagnet 119 toward the field coil 120 to produce an electric cut'- 7manner as previously described, so that the mechanical,

fuse will perform no function if the electrical detonation occurs.Should the electrical detonator fail to function for any reason, whichis improbable, the mechanical fuse will function in the mannerpreviously described and the flash from the primer will detonate theboosters 127 and 157 to detonate the charge 124 to produce a slightlydelayed explosion of the bomb 113.

In Fig. 11, another embodiment of the electric instantaneous fuse isdisclosed, including an outer fuse housing 187. which is adapted to bescrew threaded into the trailing end of a projectile, not shown, such asprojectile 15. The housing 187 is provided with a rearwardly openinginternally threaded recess 188 for receiving a plug 189, forming acarrier for the fuse assembly which is contained in an annular cavity190 thereof. The fuse as sembly includes the annular tubular member 191of insulating material, similar to the tubular member 43 and containinga small quantity of mercury 192, and provided with spaced electricalcontacts 193 and 194 which extend into the .tube. The plug 189 isprovided with a central cavity 195 containing an electric detonator orsquib 196, corresponding to the squib 41, and having one electricalconductor .197 thereof connected to the contact 193 and its otherelectrical conductor 198 connected to a field coil 199. Field coil 199is of annular formation and is disposedin the inner part of the cavity190 and includes an annular winding 200, contained in an annular,forwardly opening channel member 201 of electrical conducting material.A conductor 202 connects the field coil 199 to the contact 194. Therecess 188 extends inwardly or forwardly beyond the forward face of theplug 189 to form a chamber 203 in which is loosely disposed an annularpermanent magnet 204, the diameter of which is only slightly less thanthat of the chamber 203 but the thickness of which is substantially lessthan the thickness of the chamber, so that the magnet 204 is capable ofsliding movement longitudinally of the fuse housing 187 but incapable ofany sliding movement transversely thereof. A retaining pin 205 ismounted in the housing 187 and extends into a recess 2.06 in theperiphery of the magnet 204. Recess 206 is elongated in a directiontransversely of the magnet 204 to permit said magnet to move in adirection lengthwise of the fuse, but said pin effectively prevents anyrotation of the magnet within the chamber 204.

The forward, restricted end 207 of the fuse housing 187 is externallythreaded to be engaged by a cap 208 the closed end of which is spacedfrom the forward end of the extension 207 to form a chamber containing abooster charge 209. Extension 207 is provided with a centrally disposedflash passage 210 which communicates with the cavity 203, the openingthrough the center of magnet 204 and the cavity 195 to form a continuousflash passage between the detonator 196 and the booster 209. Theextension 207 contains a plurality of inwardly extending radiallydisposed and inwardly spring pressed pins 211 having beveled inner endswhich bear against abeveled edge of the periphery of the magnet 204 tonormally retain said magnet in a fixed position against the field coil199. The springs 212 of the pins 211 are held under tension by hearingagainst portions of the cap 208. The extension 207 is provided with asubstantially radially disposed internally threaded opening 213 whichcommunicates with the passage 210 and in which is seated a re 'cessedplug 214, forming a seat for an expansion coil spring 215 and a guidefor a 'slidably mounted substantially radially disposed partition orclosure 216. Clo sure 216 has an inner end which is substantially halfcircular in cross section and which extends through and closes flashpassage 210, intermediate the ends thereof, and which is held normallyin a closed position, as seen in Fig. 11, by the pressure of the spring215.

The fuse shown in Fig. 11 is adapted to be mounted in a rotatable typeprojectile such as the projectile 15. The fuse is normally maintained ina safe, disarmed position by the circuit breaker formed by the spacedcontacts 193 and 194 which prevents an electric current beingtransmitted from the field coil 199 to the squib 196. Also, the pin 205and the pins 211 function to normally prevent any movement of the magnet204 to provide a further safety feature; and still another safetyfeature is afforded by the partition 216 which seals the passage betweenthe squib 196 and the booster 209. When a projectile, with the fuseshown in Fig. 11 mounted therein, is fired, the rotation of theprojectile on its longitudinal axis will cause the mercury 192 tocomplete the electrical circuit between the contacts 193 and 194, in themanner previously described; will cause the pins 211 to be retractedagainst the action of their springs 212 to release the magnet 204; andwill cause the partition 216 to be retracted into the guide 214 andagainst the action of spring 215 to open the flash passage 210, all bycentrifugal force. The magnet 204 will be held against any forwardsliding movement by inertia during the flight of the projectile, butupon impact of the projectile with its target, said magnet will be movedforward in the chamber 203 by the force of inertia to produce anelectric current in the coil 199 to detonate the squib 196 and thebooster 209 for instantaneously exploding the charge, notshown, in theprojectile in which the fuse is mounted, to thereby accomplish the sameresult as the fuses shown in the other embodiments, previouslydescribed.

Fig. 12 shows a slightly modified form of the fuse structure shown inFig. 11 and wherein a housing 217 is adapted to be screw threaded intothe trailing end of a rotatable type projectile, such as the projectile15 of Fig. 1. The housing 217 is provided with a hollow forward portioncontaining an annular tube 218 of in sulating material which functionsin the same manner and. for the same purpose as the tube 191. Anelectrical field coil 219, corresponding to the field coil 199, ismoulded into an electrical insulating block 220, in which the tube 218is formed, and is connected in the same mann'erto the contacts of thetube and to an electric detonator or squib 221. The squib 221 is mountedin the central opening of the coil 219. The forward end of the opening,formed by the coil 219, is sealed by a closure 222,

and forwardly of said coil, the insulating block 220 and the forward endof the housing 217 combine to form a cavity 223, for the same purpose ascavity 203, which contains a permanent magnet 224 mounted therein, inv

the same manner and for the same purpose as the magnet 204, and retainedrelatively thereto, in the same manner and for the same purpose, by apin 225, corresponding to the pin 205, and spring pressed pins 226,corresponding to the pins 211. The block 220 combines with the rear partof the housing 217 to form a chamber for a booster charge 227, and saidblock 220 is provided with a centrally disposed flash passage 228normally closed by a partition 229, mounted in the same manner and forthe same purpose as the partition 216.

Thus it will be apparent that when the fuse of Fig. 1.2 is rotated inflight in a projectile, not shown, in which it is mounted, the contactsof the tube 218 will be electrically connected by the mercury containedtherein, the pins 226 will be retracted, and the partition 229 willlikewise be retracted, all by centrifugal force, for arming the fuseready to be discharged upon impact of the projectile with its target.Upon such impact, a forward movement of the magnet 224 by inertia willproduce the electric charge for detonating the squib 221, the booster227 will be detonated thereby to produce a flash which Will burst theperimeter of the booster casing in all directions to uniformly detonatethe main projectile charge, notshown, at its rear end to produce a veryuniform explosion of the charge. The invention as embodied in Figs. 11and 12 forms the subject of my divisional application Serial Number115,307, filed September 12, 1949, now Patent 2,688,921, dated September14, 1954.

Various other modifications and changes in the embodiments of theinvention as herein disclosed are .contemplated and may obviously berestored to without departing from the spirit and scope of the inventionas hereinafter defined by the appended claims, as only preferredembodiments of the invention have been illustrated and described.

I claim:

1. A projectile fuse comprising in combination with an electricdetonator and electrical means connected therewith and energized by theimpact of the nose of the projectile with a target for exploding thedetonator; a centrifugally operated switch interposed in the circuit ofthe detonator and electrical means, and including an annular tube ofinsulating material containing a small quantity of mercury, and spacedcontacts connected to parts of the circuit and extending into the tube,said mercury reacting to the rotation of the projectile in flight toform a ring electrically connecting the contacts for closing the switch.

2. An aerial bomb fuse comprising in combination with an electricdetonator, electrical means connected therewith and energized by theimpact of the bomb with a target for exploding the detonator, and astrip wire carried by the bomb and connected to an airplane from whichthe bomb is launched and stripped from the bomb by the movement of thebomb relatively to the airplane; an arming switch interposed in thecircuit between the electrical means and detonator, a body of fluidunder pressure normally holding said switch in open position, and meansoperated by the removal of said strip wire to release the pressure ofsaid fluid and thereby permit movement of said switch toward a closedposition for arming the bomb fuse at a predeternimed time after the bombis launched.

3. A projectile having a movable nose portion and a shaped chargeprovided with a forwardly opening conical cavity; comprisingmechanically operated electrical means, an electric detonatorelectrically connected thereto, said electrical means being disposed inthe tail end of the projectile, said mechanical means connecting theelectrical means to said movable nose portion of the projectile forenergizing the electrical means when the nose portion is actuated byimpact with a target, said mechanical means being disposed out ofalignment with the axis of the projectile.

4. In a projectile, the combination of a casing, a shaped charge in therear portion of said casing and shaped to provide a forwardly-directedcavity, an electrically-operated detonator at the rearward portionof andin detonating relation with said charge, electrical induction means forenergizing said detonator, a hollow nose supporting portion secured tosaid casing forwardly of said charge, a nose movably attached to saidportion and adapted to be moved relative thereto upon impact, and meansconnecting said nose to said induction means to energize said detonatorupon said relative movement of said nose upon impact, said connectingmeans extending spaced from the apex of said conical cavity, a hollow'member secured to said casing in the vicinity of said conical cavity andextending beyond said charge, a nose member movably attached to saidhollow member and adapted to be moved relative thereto upon impact ofthe projectile with an object, an electrical coil means secured to oneof said members, an electrical circuit connecting said coil means tosaid detonator, a magnetic means movably associated with said electricalcoil means for generating current therein and secured to the other ofsaid members, a device associated with said electrical circuit toprevent the flow of current therein to said detonator, means connectedwith said device adapted to become activated after movement of theprojectile has been initiated and before impact of the same to renderthe device inoperative to prevent the flow of current to the detonatorwhereby upon impact said nose will cause relative movement between saidcoil and magnetic means thereby generating current to energize saidcircuit to explode said detonator and thereby said charge.

6. In a projectile, the combination of a casing, a shaped charge thereinand having a conical cavity at one end, an electrically-operateddetonator in said charge spaced from the apex of said conical cavity, ahollow member secured to said casing in the vicinity of said conicalcavity and extending beyond said charge, a nose member movably attachedto said hollow member and adapted to be moved relative thereto uponimpact of the projectile with an object, an electrical coil meanssecured to one of said members, an electrical circuit connecting saidcoil means to said detonator, a magnetic means movably associated withsaid electrical coil means for generating current therein and secured tothe other of said members, whereby upon impact said nose will causerelative movement between said coil and magnetic means generatingcurrent to energize said circuit to explode said detonator and therebysaid charge.

7. In a projectile, the combination of a casing, a shaped charge in therear portion only of said casing and provided with a forwardly-directedconical cavity, an electrically-operated detonator mounted in saidcharge, electrical means for energizing said detonator, a hollow nosesupporting portion secured to said casing in the vicinity of said cavityand extending forwardly of said charge, a nose movably attached to saidportion and adapted to be moved relative thereto upon impact, meansconnecting said nose with said electrical means whereby upon saidrelative movement of said nose upon impact said electrical means willoperate to energize said detonator to explode the same and thereby thecharge, said last-named means extending along and closely adjacent theinner side walls of said casing in the space between said shaped chargeand said nose, whereby said space is substantially unobstructed.

8. In a projectile, the combination of a casing, a shaped charge thereinprovided with .a forwardly-directed cavity, an electrically-operateddetonator mounted in the rear portion of said charge, electrical meansfor energizing said detonator, a device associated with said electricalmeans for rendering the same inoperativeto affect said deonator, .meansattached to said device adapted,

after movement of the projectile has been initiated and before impact ofsame,'to render said device inoperative whereby said electrical means isplaced in an operative condition to energize said detonator, ahollownose supporting portion secured to said casing in the vicinity ofsaid cavity and extending forwardly of said charge, a nose movablyattached to said portion and adapted to be moved relative thereto uponimpact, means connecting said nose with said electrical means wherebyupon said relative movementof said nose upon impact said electricalmeans will operate to energize said detonator to explode the same andthereby the charge, said last-named means being closely adjacent theWalls of said casing be tween said shaped charge and nose to therebyleave unobstructed the space between said charge and nose.

til

9. In a projectile, a hollow casing, a shaped charge in said casinghaving a forwardly opening cavity, a nose portion over the forward endof said casing and movable relatively to said casing on impact, aninduction coil carried by said casing adjacent said nose portion, amagnet carried by said nose portion in position to induce a voltage insaid coil on impact, electrically-energized means for detonating saidcharge, and a circuit including said coil and means.

10. A projectile comprising a shell casing, a shaped charge in the rearportion of said casing, said charge having a forwardly-opening cavity, anose carried by said casing and movable with respect thereto on impact,means carried by said nose and casing and cooperable to generate avoltage in response to movement of said nose as aforesaid, a squib indetonating relation with said charge, an electric circuit including saidgenerating means and squib, means normally preventing the flow ofcurrent to said squib, and means responsive to movement of saidprojectile in flight for rendering said flow-preventing means inoperableto thereby arm said projectile.

11. In a projectile fuse for detonating shaped charges, said fusecomprising an electrical coil, a permanent magnet disposed for movementrelatively to the coil on impact of the projectile with a target, forproducing an electric current in the coil, an electric detonator adaptedto explode said charge and electrically connected to the coil, safetymeans interposed in the circuit of the coil and detonator, actuatedafter initiation of the movement of the projectile in which the fuse ismounted, for completing a circuit to the detonator whereby the detonatorwill be discharged by a movement of the magnet relatively to the coilupon impact, said coil being mounted in the nose of the projectile, saidprojectile nose being provided with a movable impact receiving portion,said magnet being connected to the movable nose portion.

12. In a projectile, a hollow casing, a shaped charge in said casinghaving a forwardly opening cavity, a nose portion over the forward endof said casing and movable relatively to said casing on impact, aninduction coil carried by said casing adjacent said nose portion, amagnet carried by said nose portion in position to induce a voltage insaid coil on impact, electricallyenergized means for detonating saidcharge, a circuit including said coil and means, a switch in saidcircuit, means urging said switch into movement toward closed position,fluid pressure means normally opposing said movement, and meansresponsive to initial movement of said projectile for releasing thepressure of said fluid pressure means to thereby permit closing of saidswitch and arming of said projectile.

13. In a projectile, a generally cylindrical casing having an ogivalnose portion, a charge in the rearward por tion of said casing, saidcharge having a forwardly-directed cavity, a cap portion over said noseportion and movable rearwardly with respect to said nose portion onimpact of said projectile, induction means including a coil carried byone said portion and cooperative to induce a voltage in said coil inresponse to relative movement of said portions, a primer in detonatingrelation with said charge, a circuit for detonating said primer, saidcircuit including said coil and an arming switch, spring means urgingsaid switch into closed position, means including a body of fluid underpressure for resisting the action of said spring means, and meansresponsive to launching of said projectile for releasing the pressure ofsaid fluid.

14. A projectile comprising a shell casing, a shaped charge in the rearportion of said casing, said charge having a forwardly-opening cavity, anose carried by said casing and movable with respect thereto on impact,generating means actuated by relative movement of said nose and casingand cooperable to generate a voltage in response to movement of saidnose as aforesaid, a squib in detonating relation with said charge, anelectric circuit including said generating means and squib, means nor-15 mally preventing the flow of current to said squib, means responsiveto movement of said projectile in flight for rendering saidflow-preventing means inoperable to thereby arm said projectile, saidgenerating means comprising a solenoid and cooperating magnet movablewith respect to said solenoid in response to impact, to generate avoltage therein, lever means carried by said casing and pivoted inresponse to movement of said nose, and flexible cable means connectingsaid lever means and magnet to move the latter.

15. In a projectile, a hollow casing, a shaped charge in said casinghaving a forwardly opening cavity, a nose portion over the forward endof said casing and movable relatively to said casing on impact, aninduction coil carried by said casing adjacent said nose portion, amagnet carried by said nose portion in position to induce a voltage insaid coil on impact, electrically-energized means for detonating saidcharge, a circuit including said coil and detonating means, a shortingelement electrically connecting the lead wires to said detonating means,and a set-back actuated element engaging said shorting element andoperable to shear the same in response to firing of said projectile.

16. A projectile as recited in claim 15, dielectric means forming atoroidal chamber coaxial of the rotation axis 16 v of said projectile, aglobule of electrolytic liquid in said chamber, and first and secondelectrical contacts in diametrically opposite relation in said chamberand connected in said circuit, said liquid forming a ring in response tospinning of said projectile to electrically connect said contacts andclose said circuit.

References Cited in the file of this patent UNITED STATES PATENTS384,662 Zalinski June 19, 1888 1,336,828 Edwards Apr. 13, 1920 1,340,546Keeran May 18, 1920 1,776,796 Ruhlemann Sept. 30, 1930 2,399,211 Daviset al Apr. 30, 1946 2,458,464 Busacker et a1. Jan. 4, 1949 FOREIGNPATENTS 1,089 Great Britain Jan. 13, 1912 506,280 France May 26, 1920166,909 Great Britain July 11, 1921 149,723 Austria May 25, 1937 91,592Sweden Feb. 24, 1938 525,333 Great Britain Aug. 27, 1940 113,685Australia Aug. 14, 1941

